Treatment of textiles with aziridinemodified polyurethanes

ABSTRACT

POLYURETHANES CONTAINING ISOCYANATE GROUPS ARE REACTED WITH ALKYLENE IMINES TO PREPARE AZIRIDINE-MODIFIED POLYURETHANES USEFUL FOR APPLICATION TO TEXTILE MATERIALS TO IMPROVE THEIR PROPERTIES, E.G., TO IMPART SHRINK RESISTANCE AND DURABLE PRESS QUALITIES. TYPICAL EXAMPLE: A POLYETHER POLYURETHANE CONTAINING FREE NCO GROUPS IS REACTED WITH ETHYLENE IMINE TO YIELD AN AZIRIDINE-MODIFIED POLYMER WHICH IS FORMED INTO AN EMULSION AND APPLIED TO A TEXTILE MATERIAL. THE TREATED TEXTILE MAY BE DIRECTLY CURED OR THE CURING OPERATION MAY BE DELAYED UNTIL THE FABRIC IS MANUFACTURED INTO A FINISHED GARMENT, THE LATTER SYSTEM BEING PREFERRED TO ATTAIN PERMANENT CREASES.

3,632,556 TREATMENT OF TEXTILES WITH AZIRIDINE- MODIFIED POLYURETHANESAllen G. Pittman, El Cerrito, and William L. Wasley,

Berkeley, Calif., assignors to the United States of America asrepresented by the Secretary of Agriculture No Drawing. Originalapplication Oct. 13, 1967, Ser. No. 675,038, now Patent No. 3,542,505,dated Nov. 24, 1970. Divided and this application Jan. 21, 1970, Ser.

Int. Cl. C08g 22/16, 45/22 US. Cl. 260-75 NH 2 Claims ABSTRACT OF THEDISCLOSURE This is a division of our copending application Ser. No.675,038, filed Oct. 13, 1967, now Pat. 3,542,505.

A non-exclusive, irrevocable, royalty-free license in the inventionherein described, throughout the world for all purposes of the UnitedStates Government, with the power to grant sublicenses for suchpurposes, is hereby granted to the Government of the United States ofAmerica.

This invention relates to and has among its objects the provision ofnovel processes for treating textile materials and the products of suchprocesses. A special object of the invention is the provision of suchtreatments involving the use of aziridine-modified polyurethanes wherebyto provide such benefits as improved shrinkage resistance and permanentpress qualities. Further objects and advantages of the invention will beevident from the following description wherein parts and percentages areby weight unless otherwise specified.

The prior art discloses that various aziridine derivatives have beenproposed for use as shrinkproofing agents for W001. See Tesoro, U.S.Pats. 3,165,375 and 3,279,882, and Textile Research Journal, June 1964,pages 523-532. Among the aziridines tested by said investigator werecertain so-called amino-aziridines (those in which the nitrogen atom ofthe aziridine rings is an amino nitrogen) and amide-aziridines (those inwhich the nitrogen atom of the aziridine rings is an amido nitrogen). Itis reported by this investigator that effectiveness of the aziridines asshrinkproofing agents is related to the basicity of the ring nitrogens,so that the amino-aziridines provide good shrinkproofing results whilethe amido aziridines do not. In fact, Patent 3,279,882 discloses thateffective shrinkproofing results are obtained with the amido aziridinesonly when they are applied conjointly with a polyamine (i.e., a basiccompound). Further disadvantages attributed to the amide aziridines bythe said investigator are that they stiffen the treated fabric and causesevere losses in abrasion resistance (Text. Res. Jur., June 1964, p.529).

We have found that a novel class of aziridine derivatives exhibits anunusual ability to improve the properties of textiles, particularlywool. Our agents are not only chemically distinct from those of theprior art, but also obviate the problems analyzed above. Some of thesigniflUnited States Patent 0 ice icant advantages provided by ouraziridine derivatives are listed below:

They provide effective shrinkproofing even when applied in smallproportions to the textile material.

They are effective per se; the conjoint application of a polyamine isunnecessary. It may be noted in this connection that application ofpolyamines to wool is hazardous because if any unreacted polyamineremains on the wool it will cause yellowing and degradation of thefibers.

They do not adversely affect the abrasion resistance of the textilematerial. In fact, the treated material often exhibits increasedabrasion resistance. In contrast, the amido aziridines studied by Tesoroare admitted to cause decrease in abrasion resistance.

They do not cause a stiffening of the fabric. This is in sharp contrastto Tesoros findings that effective shrinkproofing is coupled withstiffening; indeed, that the degree of stiffening is proportional toshrinkproofing efficiency. See Text. Res. Jour., June 1964, p. 529.

They do not effect the intrinsic properties of the fibers, such ascolor, tensile strength, flexibility, hand, porosity, etc. so that thetreated fibrous materials can be employed in any of the usual textileapplications as in fabricating shirts, skirts, trousers, and othergarments.

They provide flat-setting and durable crease qualities.

The aziridines of the invention are particularly useful in applicationsinvolving delayed curing, that is, where the aziridine is applied to thefabric, the treated fabric is manufactured into a garment provided withappropriate creases in selected areas, and the garment is then subjectedto a curing treatment so that the completed garment is not only shrinkresistant but also press-free, i.e., it can be subjected to repeatedwashings without requiring pressing to maintain the creases. Theparticular advantages of the present invention which make themespecially adapted to such use are: Our aziridines do not undergospontaneous curing; they remain in the uncured state even after longstorage of the treated fabric. The aziridines remain in the uncuredstate even if subjected to moisture at ordinary temperatures. Thus, thetreated fabrics may be subjected to moist conditions as may be requiredin certain garment fabrication steps without premature curing andwithout decomposition of the applied aziridine.

The aziridines of the invention may aptly be described asaziridine-modified polyurethanes, and have the structure:

wherein:

A is the residue of a polyether polyol or polyester polyol having avalence of n,

R is a hydrocarbon radical containing at least two carbon atoms,

R is hydrogen, halogen, lower alkoxy, or a radical of the structure f) CH: -NH-CN/ \CHR R is hydrogen or a lower alkyl radical,

n is an integer from 2 to 10, and x is an integer from 1 to 2.

The aziridine derivatives of the invention are prepared by reacting analkylene imine, such as ethylene, propylene, or butylene imine, with apolyether (or polyester) polyurethane containing free isocyanate groups.This simple 3 4 reaction establishes the desired aziridine-modificationof preferred to use the polyether-based polymers, for examthe startingpolymer. A typical, but by no means limiting, ple, the NCO-containingpolyurethanes derived from polyexample of the synthesis is illustratedbelow: alkylene ether glycols such as polyethylene ether glycols,

ll H 1 CN NH-COHZOHZCHZOHZ- OCNH N C O Isocyanate-terminated jmpolyether polyurethane 2052-6112 Ethylene imlne H CH3 i 3 s i t t l P IN-C-NH -H-NH-o-o OHlCH20H2OHl0 oNH NHCN Aziridine-modified /m polyetherpolyurethane CH2 CH1 (In the above formulae, m represents the number oftetrapolytrimethylene ether glycols, polytetramethylene ethermethyleneether repeating units. This may range, for exg ypolypropyleneether glycols, and the like. ample, about from 5 to THEPOLYMER INTERMEDIATES The reaction is carried out at about to C., and 25under essentially anhydrous conditions to avoid hydrolysis of theisocyanate groups. The alkylene imine is supplied in excess to ensureconversion of all isocyanate groups to aziridine groups. It is evidentfrom the formulae above that modification in the azin'dine rings can beeffected 3O Polyether (or polyester) polyurethanes containing freeisocyanate groups useful as intermediates for the present invention maybe prepared, as well known in the art, by reacting a polyether (orpolyester) polyol with a. polyisocyanate, using an excess of the latterto ensure provision of free isocyanate groups in the product. A typical,

by selection of the alkylene imine reactant. For example, but by nomeans limiting, example is illustrated below:

HO CH CHr-CH CHaO H Polyether polyol 2 No 0 NC 0 Polyisocyanate 0 l f llOCN NH--C-O\CH1-CH -CH CHgOTO-NH NCO Isocyanate-terminated polyetherpolyurethane if propylene imine is used instead of ethylene imine, the(In the above formulae, in represents the number of tetraaziridine ringswill be of the structure methyleneether repeating units. This may range,for ex- CHZ ample, about from 5 to 50.) Representatives examples ofpolyisocyanates which may be employed for reaction with the polyether(01' polyester) gpolyol include:

In other words, in this case R" (in Formula I) is methyl.toluene-2,4-diisocyanate Referring to Formula I, above, it is evidentthat selectoluene,2,6-diisocyanate tion of the polymer intermediate-thepolyether or polycommercial mixtures of toluene-2,4 and2,6-diisocyanates ester polyurethane containing free isocyanate groupsethylene diisocyanate will determine the values of A, R, R, n, and x.The prepaethylidene diisocyanate ration of these intermediate is wellknown in the art; propylene-1,Z-diisocyanate they are widely used in theproduction of urethane foams cyclohexylene-1,2-diisocyanate for paddingand insulation applications, and in the production of elastomers.Although the preparation of these cyclohexylene-1,4-diisocyanatem-phenylene diisocyanate intermediates forms no part of the presentinvention, this 3,3'-diphenyl-4,4-biphenylene diisocyanate subject willbe explained below to illustrate the wide range 4,4'-biphenylenediisocyanate of intermediates which may be employed in producing3,3'-dichloro-4,4'-biphenylene diisocyanate the aziridinederivatives ofthe invention. Thus, for the 1,6-hexamethylenediisocyanate purposes ofthe invention, the intermediate may be any1,4-tetramethylene-diisocyanate polyether or polyester polyurethanewhich contains at 1,10-decamethylenediisocyanate least two free NCOgroups per polymer molecule. Pre- 1,S-naphthalenediisocyanate ferred arethe polymer intermediates having a molecular cumene-2,4-diisocyanateweight of at least 500, more preferably those having a4-methoxy-l,B-phenylenediisocyanate molecular weight of at least 1000.Also, it is generally 4-chloro-l,3-phenylenediisocyanate4-bromo-1,3-phenylenediisocyanate 4-ethoxy-1 ,3 -phenylenediisocyanate2,4'-diisocyanatodiphenylether 5,6-dimethyl-1,3-phenylenediisocyanate2,4-dimethyl-1,3-phenylenediisocyanate 4,4'-diisocyanatodiphenyletherbenzidinediisocyanate 4,6-dimethyl-1,3-phenylenediisocyanate9,10-anthracenediisocyanate 4,4'-diisocyanatodibenzyl 3 ,3-dimethyl-4,4'-diisocyanatodiphenylmethane2,6-dimethyl-4,4'-diisocyanatodipheny1 2,4-diisocyanatostilbene 3,3'-dimethyl-4,4'-diisocyanatodiphenyl 3,3-dimethoxy-4,4-diisocyanatodiphenyl 1,4-anthracenediisocyanate 2,5-fiuorenediisocyanate 1,8-naphthalenediisocyanate2,6-diisocyanatobenzfuran 2,4,6-toluenetriisocyanate, andp,p,p"-triphenylmethane triisocyanate.

It is evident that the selection of the polyisocyanate reactant willdetermine the values of R and R in Formula I. For example, where thereactant is a hydrocarbon diisocyanate, R will be a hydrocarbon radicaland R will represent a hydrogen atom forming part of said hydrocarbonradical. Where the reactant contains a substituent such as chlorine ormethoxy-as would be the case with, for example, 4-chloro-1,3-phenylenediisocyanate or 4- methoxy-1,3-phenylene diisocyanateR will be thehydrocarbon residue of the reactant and R will be thesubstituentchlorine or methoxy in the given examples.

The polymer intermediates useful for the purposes of the invention may,in turn, be derived from any of a wide variety of polyether polyols andpolyester polyols, and

representative examples of these polyols are described below:

Among the polyether polyols which may be so used are those prepared byreaction of an alkylene oxide with an initiator containing activehydrogen groups, a typical example of the initiator being a polyhydricalcohol such as ethylene glycol. The reaction is usually carried out inthe presence of either an acidic or basic catalyst. Examples of alkyleneoxides which may be employed in the synthesis include ethylene oxide,propylene oxide, any of the isomeric butylene oxides, and mixtures oftwo or more different alkylene oxides such as mixtures of ethylene andpropylene oxides. The resulting polymers contain a polyether backboneand are terminated by hydroxyl groups. The number of hydroxyl groups perpolymer molecule is determined by the functionality of the activehydrogen initiator. For example, a difunctional alcohol such as ethyleneglycol (as the active hydrogen initiator) leads to polyether chains inwhich there are two hydroxyl groups per polymer molecule. Whenpolymerization of the oxide is carried out in the presence of glycerol,trifunctional alcohol, the resulting polyether molecules contain anaverage of three hydroxyl groups per molecule. Even higherfunctionality-more hydroxyl groups-is obtained when the oxide ispolymerized in the presence of such polyols as pentaerythritol,sorbitol, dipentaerythritol, and the like. In addition to those listedabove, other examples of polyhydric alcohols which may be reacted withalkylene oxides to produce useful polyether polyols include:

propylene glycol trimethylene glycol 1,2-butylene glycol 1,3-butanediol1,4-butanediol 1,5-pentanediol 1,2-hexylene glycol 1,10-decanediol1,2-cyclohexanediol 2-butene-1,4-diol 3-cyclohexene-1,l-dimethanol Cir4-methyl-3-cyclohexcne-1,l-dimethanol 3-methylenc-1.,5-pentanedioldiethylene glycol (Z-hydroxyethoxy)-1-propanol4-(2-hydroxyethoxy)-l-butanol 5- Z-hydroxypropoxy) l-pentanol1-(Z-hydroxymethoxy)-2-hexanol 1- 2-hydroxypropoxy -2-octanol3-allyloxy-LS-pentanediol 2-allyloxymethyl-2-methyl-1,3-propanediol(4-pentyloxy) methyl] 1,3-propanediol 3- (o-propenylphenoxy)1,2-propanediol thiodiglycol 2,2'- [thiobis (ethyleneoxy) ]diethanolpolyethyleneether glycol (molecular weight about 200)2,2-isopropy1idenebis (p-phenyleneoxy)diethanol 1,2, 6-hexanetriol1,1,1-trimethylolpropane 3-(Z-hydroxyethoxy)-1,2-propanediol3-(2-hydroxypropoxy)-1,2-propanediol 2,4-dirnethyl-2- 2-hydroxyethoxymethylpentanediol- 1 ,5

1,1,1-tris[ 2-hydroxyethoxy methyl] ethane 1,1,1-tris[ (Z-hydroxypropoxymethyl] propane triethanolamine triisopropanolamine resorcinolpyrogallol phloroglucinol hydroquinone 4,6-di-tertiarybutyl catecholcatechol orcinol methylphloroglucinol hexylresorcinol3-hydroxy-2-naphthol 2-hydroxy-1-naphthol Z,5-dihydroxy-1-naphtholbis-phenols such as 2,2-bis-(p-hydroxyphenyl)propane andbis-(p-hydroxyphenyl)methane 1,1,2-tris-(hydroxyphenyl) ethane 1,1,3-tris- (hydroxyphenyl propane.

An especially useful category of polyether polyols are thepolytetramethylene glycols. They are prepared by the ring-openingpolymerization of tetrahydrofuran, and contain the repeating unit in thepolymer backbone. Termination of the polymer chains is by hydroxylgroups.

The polyester polyols which may be employed as precursors for theaziridines of the invention, are most readily prepared by condensationpolymerization of a polyol with a polybasic acid. The polyol and acidreactants are used in such proportion that essentially all the acidgroups are esterified and the resulting chain of ester units isterminated by hydroxyl groups. Representative examples of polybasicacids for producing these polymers are oxalic acid, malonic acid,succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid,azelaic acid, sebacic acid, brassylic acid, thapsic acid, maleic acid,tumaric acid, glutaconic acid, a-hydromuconic acid, fi-hydromuconicacid, a-butyl-et-ethylglutaric acid, a,,8-diethylsuccinic acid, 0-phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid,trimellitic acid, trimesic acid, mellophanic acid, prehnitic acid,pyromellitic acid, citric acid, benzenepentacarboxylic acid,1,4-cyclohexanedicarboxylic acid, diglycollic acid, thiodiglycollicacid, dimerized oleic acid, dimerized linoleic acid, and the like.Representative examples of polyols for forming these polymers includesethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol,butene-1,4-diol, 1,5-pentane diol, 1,4-pentane diol, 1,3- pentane diol,1,6-hexane diol, hexene-l,6-diol, 1,7-heptane diol, diethylene glycol,glycerine, trimethylol propane, 1,3, 6-hexanetriol, triethanolamine,pentaerythritol, sorbitol,

and any of the other polyols listed hereinabove in connection with thepreparation of polyether polyols.

An interesting class of polyester polyols are those which includepolyether units so that they may be considered as polyester polyols oras polyether polyols, depending on Whether the ester or the ether groupsare in majority. The compounds may be produced by the condensationpolymerization of any of the above-mentioned polybasic carboxylic acidswith a polyalkyleneether glycol-typically, a polyethyleneether glycolhaving a molecular weight of about 200 to 2000-using the glycol in therequired proportion to assure termination by hydroxyl.

Esters of the hydroxyl-containing acid, ricinoleic acid, form anothercategory of useful polyester polyols. Typ cally, one can use esters ofricinoleic acid with ethylene glycol, propylene glycol, glycerol,pentaerythritol, diglycerol, dipentaerythritol, polyalkyleneetherglycols, and the like. Representative of this category of polyesterpolyols is castor oil which is composed mainly of the tri-glyceride ofricinoleic acid.

APPLICATION OF THE AZIRIIDINE TO II-IE TEXTILE The aziridines of theinvention may be applied to the textile in various ways. One techniqueinvolves applying the aziridiue as such to the textile, using warming ifnecessary to make the aziridine flow, and distributing it with calenderrolls or the like. A preferred technique involves dissolving theaziridine in an inert, volatile solvent and applying the resultingsolution to the textile material. Typical of the solvents which may beused are benzene, toluene, xylene, dioxane, diisopropyl ether, dibutylether, butyl acetate, chlorinated hydrocarbons such as chloroform,carbon tetrachloride, ethylene dichloride, trichloroethylene,1,3-dichlorobenzene, fiuorohydrocarbons such as benzotrifluoride, 1,3bis (trifluoromethyl)benzene, etc., petroleum distillates such aspetroleum naphthas, etc. Usually it is preferred to use the aziridinesin the form of aqueous emulsions. These can be prepared by customarytechniquesagitation of the aziridiue with water and a conventionalemulsifying agent such as an alkylphenoxypoly (ethyleneoxy)ethanol,polyoxyethylene sorbitan monopalmitate, polyoxyethylene lauryl ether,polyoxyethylene-polyoxypropylene stearate, sorbitan monopalmitate,sorbitan monolaurate, and the like. The concentration of the aziridiuein the dispersion-this last term being herein employed in a genericsense to include solutions and emulsions-is not critical and may bevaried depending on such circumstances as the solubility characteristicsof aziridine, the amount of aziridiue to be deposited on the fibers, theviscosity of the dispersion, etc. In general, a practical range ofconcentration would be from about 1% to about 25%. The dispersion may bedistributed on the textile material by any of the usual methods, forexample, by spraying, brushing, padding, dipping, etc. -A preferredtechnique involves immersing the textile in the dispersion and thenpassing it through squeeze rolls to remove the excess of liquid. Suchtechnique as blowing air through the treated textile may be employed toreduce the amount of liquid which exists in interstices between fibrouselements. In any case, the conditions of application are so adjustedthat the textile material contains the proportion of aziridiue desired.Generally, the amount of aziridiue is about from 0.5 to based on theweight of the textile material but it is obvious that higher proportionsmay be used for special purpose. In treating textiles such as fabricsthe amount of aziridiue is usually limited to a range of about 0.5 to10% to attain the desired end such as shrink resistance withoutinterference with the hand of the textile.

After application of the aziridine, the treated textile is cured(heated) to effect an insolubilization of the applied aziridiue and topromote bonding of the aziridine to the textile. Although the mechanismof bonding has not been identified, bonding is known to occur and it isbelieved to involve chemical combination of the aziridiue with activeradicals present in the textile substrate, these active radicalsincluding carboxyl, hydroxyl, amino, and thiol groups. Such groups are,of course, present in many textile materials including wool, animalhair, leather, and other proteinaceous materials; cotton, rayon, linen,and other cellulosic fibers; nylon, polyurethanes, and many othersynthetic fibers.

In cases where the aziridiue is applied as a dispersion, that is, asolution, emulsion, or suspension, the solvent or other volatiledispersing medium is preferably evaporated prior to the curingoperation. Such prior evaporation is not a critical step and theevaporation may be simply effected as part of the curing step. Thetemperature applied in the curing step is not critical and usually iswithin the range from about 50 C. to about 150 C. It is obvious that thetime required for the curing will vary with such factors as thereactivity of the selected aziridine, the type of textile material, andparticularly the temperature so that a lower curing temperature willrequire a longer curing time and vice versa. It will be further obviousto those skilled in the art that in any particular case the temperatureof curing should not be so high as to cause degradation of the textileor the aziridiue. In many cases an adequate cure is effected by heatingthe treated textile in an oven at about C. for about 5 to 60 minutes.

Although the present invention is of particular advantage in itsapplication to wool, this is by no means the only type of fiber whichcomes into the ambit of the invention. Generically, the invention isapplicable to the treatment of any textile material and this materialmay be in any physical form, e.g., bulk fibers, filaments, yarns,threads, slivers, roving, top, webbing, cord, tapes, woven or knittedfabrics, felts or other non-woven fabrics, garments or garment parts.Illustrative examples of textile materials to which the invention may beapplied are: Polysaccharide-containing textiles, for instance, thoseformed of or containing cellulose or regenerated celluloses, e.g.,cotton, linen, hemp, jute, ramie, sisal, cellulose acetate rayons,cellulose acetate-butyrate rayons, saponified acetate rayons, viscoserayons, cuprammonium rayons, ethyl cellulose, fibers prepared fromamylose, algins, or pectins; mixtures of two or more of such polysaccharide-containing textiles. Protein containing textiles, forinstance, those formed of or containing wool, silk, animal hair, mohair,leather, fur, regenenated protein fibers such as those prepared fromcasein, soybeans, peanut protein, zein, gluten, egg albumin, collagen,or keratins, such as feathers, animal hoof or horn. Mixtures of any twoor more protein-containing textiles. Mixtures of polysaccha-Iide-containing textiles and protein-containing textiles, e.g., blendsof wool and cotton; wool and viscose, etc. Textiles formed of orcontaining synthetic resins, e.g., alkyd resins, polyvinyl alcohol,partially esterified or partially etherified polyvinyl alcohol, nylon,polyurethanes, polyethylene glycol terephthalate, polyacrylonitrile,polyethylene, polypropylene, polyvinyl chloride, and polyvinylidenechloride. Blends of natural fibe'rs such as cotton or wool withsynthetic fibers such as nylon, polyethyleneglycol terephthalate,acrylonitrile, etc. Inorganic fibers such as asbestos and glass fibers.The applications of the teachings of the invention may be for thepurposes of obtaining functional or decorative effects such asshrinkproofing, developing permanent crease qualities, sizing,finishing, increasing abrasion resistance, increasing gloss ortransparency, increasing water-, oil-, and soil-repellency, increasingadhesion or bonding characteristics of the substrates with rubber,polyester resins, etc.

DELAYED CURE SYSTEM A particular embodiment of this invention isconcerned with the production of wool products which exhibit not onlyshrink resistance but also permanent press qualities. Heretofore, no onehas been able to impart this combina tion of useful properties to wool.Existing wool shrinkproofing treatments do lead to dimensionally-stablefabrics; however, when the fabrics are washed or drycleaned they have amussy appearance and must be pressed. Creases have been set in woolengarments by, for example, treatment with reducing agents such asammonium thioglycollate or sodium bisulphite. The creases, however, donot withstand aqueous laundering nor generally more than 1 or 2dry-cleanings. Of course, no shrinkproofing is attained with thesecreasing procedures. Attempts to combine wool shrinkage treatments withcreasing treatments have not been successful in that although shrinkagecan be controlled, creases are lost after aqueous laundering and thefabrics need ironing for next appearance. Various materials such asmelamine-formaldehyde resins, urea-formaldehyde resins,dihydroxy-ethylene dimethylol urea, or alkyl carbamates, which arecommercially used in producing permanently creased garments of cotton orcotton-synthetic blends have proved entirely unsuccessful when appliedto wool.

However, these problems are obviated by the present invention. Byapplication of our aziridines to wool fabrics one attains resistance toshrinkage, a smooth wrinkle-free appearance after washing ordry-cleaning so that no ironing is required, and creases and pleatsimparted to the fabric are permanentthey withstand repeated aqueouslaundering or non-aqueous dry-cleaning.

This embodiment of the invention is most profitably practiced in asystem which incorporates a delayed cure, that is, the aziridine isapplied to the fabric but curing is delayed until the fabric has beenmade up into the desired product which may be, for eXarnple, a completedgarment. The curing then not only bonds the aziridine to the fabric, butalso renders permanent the creases or pleats which have been imparted tothe fabric. Typical ways of practicing this embodiment of the inventionare described in detail below:

The aziridine is applied to the fabric using a solution or emulsion ofthe aziridine, as described hereinabove. The conditions of applicationmay be adjusted to vary the amount of aziridine deposited on the fabric.Usually, it is preferred to deposit about 0.2 to 20% of the aziridine,based on the weight of the fabric. In a preferred modification of theprocedure a reducing agent, such as sodium bisulphite, is incorporatedin the liquid preparation of the aziridine. However, as hereinafterexplained the reducing agent may be applied at a later stage in theprocess. The treated fabric is then dried to remove the solvent or othercarrier in which the aziridine was dispersed for the application step.The drying may be in air at ordinary (room) temperature, or, warm airmay be applied to increase the rate of evaporation. To avoid prematurecuring, the temperature of the treated fabric should be kept below about50 C. However, since curing does not occur immediately, short exposuresto higher temperatures are permissible.

The fabric containing the aziridine in its uncured state is then made upinto the desired product. This may be, for example, a garment, in whichcase the fabric would be subjected to the usual garment-makingoperations of cutting, sewing, and pressing. Included in theseoperations would be formation of creases or pleats in selected areas bythe usual pressing methods employed by the tailor. In the event that areducing agent was not co-applied with the aziridine, then a reducingagent may be applied to the textile during the moistening step whichcommonly forms a part of the pressing operation. For example, an aqueoussolution of the reducing agent may be sprayed on the textile,particularly in those areas where it is intended to form creases orpleats. Enough of the solution is usually applied so there is about 0.1to 2% of the reducing agent, based on the weight of fabric. It is to beparticularly emphasized that the production of garments need not followdirectly after the axiridine treatment of the fabric. Indeed, the fabriccontaining the uncured aziridine can be held for long periods withoutdanger of spontaneous curing. The aziridines of the invention areparticularly characterized by their stability, i.e., their ability toremain in an uncured state for long periods of time. Moreover, theirstability is not affected by moisture. If moisture is applied (asnecessary in certain garment fabricating steps) there is no danger ofpremature curing.

The garment or other textile article is then subjected to a curingoperation to insolubilize the aziridine and bond it to the wool fibers.Typically, the curing is accomplished by placing the garments in an ovenwhere they are maintained at a temperature and for a time sufiicient tocause the desired curing of the applied aziridine. In general,temperatures of at least 50 C., preferably about l00l50 C., are appliedfor a period of about 560- minutes. The product after removal from theoven is now ready for use or for sale and, as previously noted, exhibitsnot only resistance to shrinkage when washed but also retains itspleats, creases, or other conformations imparted to the garment. Also,when washed, the products retain a neat appearance free from wrinklingor mussiness so that they are truly press-free, i.e., no pressing isneeded even after repeated washings.

As noted hereinabove, where permanent crease qualities are desired, areducing agent is preferably aplied to the textile, concomitantly withapplication of the aziridine or in a later ste but prior to curing.Representative examples of reducing agents include: Inorganic sulphidessuch as alkali metal, alkaline earth metal, ammonium, etc., sulphidesand hydrosulphides. Organic compounds containing a thiol group, as, forexample, thioglycollic acid, or its salts such as the alkali metal orammonium salts; betamercapto ethanol; monthio glycerol; dithio-glycerol;butyl mercaptan; thiomalic acid or its salts; thio-lactic acid or itssalts; thiophenol; thiocresol; etc. Formamidine sulphinic acid, alsoknown as iminoaminomethane sulphinic acid betaine. Formaldehydesulphoxylates, generally used in the form of their alkali metal, zinc,or ammonium salts. Alkali metal or ammonium sulphites, bisulphites andhydrosulphites. Aldehyde or ketone addition products with sulphites orbisulphites, e.g., sodium formaldehyde bisulphite, sodium acetonebisulphite, etc. Generically, the reducing agents used in accordancewith the invention may be defined as sulphur-containing, reductive,disulphidesplitting agents because of the fact that they all containsulphur in their structures and because they have the ability to openthe disulphide (cystine) linkage in the wool molecule, generallyconverting a single disulphide (SS) bond into two thiol (SH) groups.

The amount of reducing agent is not critical and may be varied dependingon such circumstances as the efiicacy of the agent selected, thedurability of set desired in the product, the character of the fibersbeing treated, etc. Even minute amounts of the reducing agent willprovide some degree of improvement. Usually, the reducing agent is usedin an amount from about 0.1 to about 2%, based on the weight of thetextile substrate being treated. It is, of course, obvious that thereducing agent should not be applied in such a high proportion as woulddegrade the textile substrate.

Although the use of a reducing agent in conjunction with our aziridinesis primarily of advantage in treatments where the substrate is to beprovided with durable creases or other configurations, it is within thebroad ambit to employ the reducing agent in other procedures, e.g., oneswherein creasing is not involved. The advantage of the reducing agent isthat it enhances bonding of the aziridine to the textile substrate.Thus, generically, the invention includes in its broad compass anytextile-treat ing procedure wherein the reducing agent is used inconjunction with our aziridines, and is applied to the textileconcomitantly with the aziridine or at any earlier or later stage, priorto the curing step.

EXAMPLES The invention is further demonstrated by the followingillustrative examples.

Washing procedure for shrinkage tests: The samples were Washed in areversing agitator-type household wash- Preparation ofaziridine-modified polytetramethyleneether polyurethane The startingmaterial for this synthesis was a commercial liquid polyurethane havinga molecular weight of 1 about 2000 and an isocyanate (NCO) content of4.1%.

It is believed to have the structure wherein A represents the residue ofa polytetramethyl- 2 enether glycol containing about twenty-five EXAMPLE2 Application of aziridinemodified polytetramethyleneether polyurethaneThe emulsion prepared as described above in Example 1 was diluted withWater (to levels indicated below) and applied to swatches of wool. Insome instances, measured amounts of NaHSO were added to the emulsions.

The treatments in each case were as follows: Wool swatches were immersedin the emulsion bath until completely wet-out, then the swatches wererun through a squeeze roll to attain a Wet pick-up of 80100%, based onthe Weight of the fabric. The damp fabrics were dried in air at roomtemperature.

Next, the dried fabrics were creased: Each swatch was moistened byspraying with water, folded, and then subjected to steaming and pressingon a tailors hot-head press. The fabrics were steamed for -20 seconds,then pressure (60-80 p.s.i.) and heat (ca. 140-150" C.) applied forseconds. The creased swatches were then cured in a forced draft oven at300 F. for 20 minutes.

The cured swatches were then given three 75-minute washes (as describedabove) and tumble-dried after each wash. The swatches were measured forshrinkage and examined for crease retention and over-all appearanceafter each tumbler drying (following each wash).

In a first series of runs, applied to an undyed woolen fabric, thefollowing results were obtained:

TABLE I 1st Washing and drying 2nd washing and drying 3rd washing anddrying Conc oi aziridinc in treating Area shrink- Area shrink- Areashrinkemulsion, percent age, percent Appearance l age, percentAppearance 1 age, percent Appearance 1 2.1 G 1. 6 F 2. 4 P

2. 0 G 1. 5 F 2.0 P 2(p1us 1% NaHSO3) 2.3 E 2.0 E 2.7 E None (untreatedwool) 18.1 28, 3

1 Fabric appearance was rated as follows: Excellent (E)-sharp crease,fabric flat and in no need of ironing. Good (GO-sharp crease, fabricflat but could use slight touching up with the iron. Fair (F)crcasestill visible but not sharp, some wrinkling, needs definite ironing.Poor (P)-n0 crease visible, badly wrinkled.

(A) Two hundred grams (0.1 mole) of the polyurethane were dissolved in300 grams of toluene. While stirring the solution, 8 grams (0.2 mole) ofethylene imine were added dropwise. During the addition, the temperatureof the solution was not allowed to exceed approxi- In a second series ofruns the treatments and tests were applied to an undyed worsted (wool)fabric which in other tests was found to be considerably more difficultto stabilize than the woolen fabric of the first series. The resultswith the worsted fabric are given below:

TABLE 111 1st Washing and drying 2nd Washing and drying 3rd washing anddrying Cone. of aziridine in treating Area shrink- Area shrink- Areashrinkemulsion, percent age, percent Appearance 1 age, percentAppearance 1 age, percent Appearance 1 4 2. 8 1. 3 E 2. 2 G 3 3. 2 3. 2G 5. 2 F 2 (plus 1% NaHSO 3.5 2.0 3.0 E None (untreated wool) 46. 6 59.7

1 Fabric appearance was rated as described in Table 1.

mately C. At the end of the addition, an infra-red EXAMPLE 3 spectrum ofthe solution revealed no residual NCO group. This indicated preparationof the desired aziridine derivative.

(B) To a 100-gi'am sample of the aziridine solution, prepared asdescribed above, was added 4 grams of a commercial oil-solubleemulsifying agent, an alkylphenoxypoly(ethyleneoxy)ethanol. The mixturewas stirred rapidly and cc. of water were slowly added. The thickwater-in-oil emulsion was transferred to a blender and an additional 200cc. of water was added while stirring at high speed. The resultingoil-in-water emulsion of the aziridine was used as a stock supply anddiluted with water as needed.

Examination of treated fabrics at intervals for delayed-cure featuresThe emulsion prepared as described in Example 1 was diluted to anaziridine concentration of 2%. In one of the runs, the diluted emulsionper se was used; in a second run 2% of NaHSO was added.

Wool fabric was treated as follows: Swatches of the W001 were wet-out inthe emulsion bath, pressed to wet pick-up, and air-dried at roomtemperature. The dried fabrics Were then stored at room temperature, andafter certain times of storage (3, 8, 15, and 30 days) were creased andcured as described in Example 2. The

13 swatches were then subjected to four 75-minute washes withtumble-drying after each wash. The results are tabulated below:

1 Appearance was rated as described in Table I.

2 In this run, the re-moistening of the fabric (part of the creasingoperation) was accomplished by spraying with an aqueous solutioncontaining 2% NaHSO 3 After 2 washes.

OCN

EXAMPLE 4 The starting material for this synthesis was a commercialliquid polyether polyurethane having a molecular weight of about 850 andan isocyanate (NCO) content of about 9.5%. It is believed to have thestructure wherein A represents the residue of a polytetramethyleneetherglycol containing about seven units.

One hundred grams (0.12 mole) of the liquid polyurethane was dissolvedin 300 ml. of dry benzene. While stirring, 13 ml. (0.26 mole) ofethylene imine was added at a rate slow enough that the reactiontemperature did not rise above 40 C.

An emulsion containing 3% of the aziridine-modified polyurethane wasprepared as follows: To 47 grams of the solution of the aziridinepolymer, prepared as described above, was added 1 gram of a commercialemulsifier, Tris- (polyoxyethylene)sorbitan monopalmitate, and 450 ml.of water and applying rapid agitation in a blendor. More diluteemulsions were prepared by incorporating water in this stock emulsion.

Samples of wool flannel were treated with the emulsions by padding withthe emulsion, squeezing through rollers to remove excess liquid, andthen curing in an oven for minutes at 300 F.

The treated samples were then tested for shrink resistance, using theAccelerotor method. In this test the fabric samples are milled at 1700r.p.m. for 2 minutes at 42 C. in an Accelerotor with aqueous sodiumoleate (0.5%) solution, using a liquor-to-wool ratio of 50 to 1. Afterthis washing operation, the samples were measured to determine theirarea and the shrinkage calculated from the original area. This is a verysevere test which applied 14 to untreated wool samples gives an areashrinkage of 40- 50%. The Accelerotor is described in American DyestuffReporter, vol. 45, p. 685, Sept. 10, 1956.

The results obtained are tabulated below:

Concentration of aziridine-modified polyurethane in Area shrinkageemulsion, (Accelerotor test), percent: percent 3 1 1.5 2 0.4 3 None(control) 42 EXAMPLE 5 The starting material for the synthesis was acommercial liquid polyether polyurethane having a molecular weight ofabout 1300 and an isocyanate (NCO) content of 6.5%. It is believed tohave the structure One hundred grams (0.077 mole) of the liquidpolyurethane was dissolved in 200 grams of dry benzene. To this solutionwas added 7 grams (0.16 mole) of ethylene imine at a rate slow enough sothat the temperature of the reaction mixture did not rise above 35 C.Five minutes after the last of the ethylene imine had been added, the IRspectrum of the reaction mixture showed that no free NCO was present.

Emulsions were prepared of the aziridine-modified polyurethane, andthese were applied to woo] flannel, and tested for shrinkage, all asdescribed above in Example 4. The results are tabulated below:

Concentration of aziridine-modified polyurethane in Area shrinkageemulsion, (Accelerotor test), percent: percent 3 3 0.5 5 None (control)42 EXAMPLE 6 A polypropyleneether glycol of molecular Weight about 6000was reacted with toluene diisocyanate in conventional manner to form anisoeyanate-termined polyurethane. This, in turn was reacted withpropylene imine to form an aziridine modified polyurethane with terminalgroups of the structure Fifty grams of the aziridine-modifiedpolymerhaving a molecular weight of 6300 -6800 and containing 0.36 to0.38 milliequivalent of imine per gram of polymerwas dissolved in 50grams of benzene and 2 grams of a commercial emulsifier, apolyoxyethylene-polyoxypropylene monostearate, was added. While stirringthe solution in a blendor, water was gradually added to make 1000 gramsof an emulsion.

A sample of wool flannel was immersed in the emulsion for 1 minute, thenpassed through squeeze rollers, and then dried in air. From the increasein weight of the fabric the uptake of polymer was found to be 4%. Thetreated fabric was cured (300 (R, minutes), then tested for shrinkage bythe Accelerotor method described above. Area shrinkage was found to be1%. A sample of the same fabric but untreated shrank 39.7% in area bythe same test.

EXAMPLE 7 A series of experiments were carried out to compare theeffectiveness of the aziridine derivatives of the invention with that ofvarious commercial products recommended for shrinkproofing applications.The various products tested were:

(A) The aziridine-modified polyalkyleneether polyurethane describedabove in Example 1: It was applied in the form of 2% emulsion to whichhad been added sodium bisulphite (1% (B) A polyamide modified byreaction with epichlorhydrin: This material is commercially available asa Watersoluble resin (Kymene manufactured by Hercules Co.) and containsepoxide linkages available for reaction with wool and for crosslinking.This product was applied in form of a 2.5% solution in water, and towhich was added sodium bisulphite (1%).

(C) \A polyacrylate containing methylol groups (CH OH) which cancross-link and/or react with hydroxy groups in wool by elimination ofwater: The main component of the polymer is a soft acrylate, polybutylacrylate. It is sold under the name HA-8 by Rohm and Haas Co. for W001shrinkproofing and other uses. It was used with an acid catalyst, ZnNOin accordance with the manufacturers recommendation. It was applied inthe form of a 4% emulsion, to which was added sodium bisulphite 1% (D) Aurea-formaldehyde condensation product, consisting basically ofdihydroxyethylene dimethylol urea:

It is widely used in applications to cotton and other cellulosictextiles to impart permanent press qualities. It was used, following themanufacturers recommendation in conjunction with an acid catalyst, ZnNO'It was applied in the form of 10% aqueous solution to which was alsoadded 1% sodium bisulphite.

Samples of a wool fabric were treated with the various agents describedabove, using the following technique in each case. The fabric waswet-out in the aqueous solution or emulsion of the agent, put throughsqueeze rolls to 80100% wet pick-up, and dried in air overnight. Thenext day the samples were moistened by spraying with water and werecreased by folding and application of steam and pressure. The creasedsamples were then cured in an oven 3l0 F. for minutes.

The cured samples were then subjected to three 75- minute washes withtumble drying after each wash. After this the samples were measured forshrinkage and assayed for retention of creases and general appearance.The results obtained are tabulated below:

Properties after three 75-min. washes 1 Appearance was rated asdescribed in Table L 1 6 EXAMPLE 8 Experiments were carried out tocompare the effectivenesses of the process of the invention with onewherein a commercially-employed shrinkproofing treatment was followed bytreatment with sodium bisulphite.

A sample of undyed worsted (wool) fabric was given a shrinkproofingtreatment by application of polyhexamethylene sebacamide throughinterfacial polymerization, as disclosed in Pat. 3,078,138. Inparticular, the fabric was first immersed in an aqueous solution ofhexamethylene diamine (1.5%) and sodium carbonate (1.5%), run throughsqueeze rolls, then immersed in a solution of sebacoyl chloride (2.0%)in a volatile petroleum hydrocarbon solvent, run through squeeze rolls,and washed in water to remove unreacted materials, and dried. The fabricwas then Wet-out with an aqueous 2% solution of sodium bisulphite andcreased by folding an application of steam and pressure, as described inExample 2. The treated fabric was then subjected to a 75-minute wash, asdescribed above, and tumble dried. It was observed that the crease haddisappeared. In contrast, a sample of the same fabric treated asdescribed in Example 2 with a 2% emulsion of the aziridine-modifiedpolyurethane and 1% sodium bisulphite, retained its creases even afterfour 75-minute washes (each followed by tumble drying). This unusualdurability of the creases plainly indicates that our process involves asynergistic effect between the aziridine-modified polyurethane and thebisulphite.

EXAMPLE 9 A hydroxy-terminated polyethylene adipate of molecular weightapproximately 6500 was end-capped by reaction with an excess of toluenediisocyanate to produce a polyether polyurethane with terminal NCOgroups. One mole of this polymer was then reacted with two moles ofethylene imine to produce an aziridine-terminated polyetherpolyurethane. A 2% emulsion of this aziridine-modified polymer wasprepared as in Example 1, part B, and wool fabric was treated with theemulsion as described in Example 2. After four 75-minute washes thetreated fabric showed 3% shrinkage in the warp and 2% shrinkage in thefill directions, while the control (untreated wool fabric) had shrunk30% in the warp and 24% in the fill under the same washing conditions.

Having thus described our invention, we claim:

1. A dispersion, in a liquid carrier, of

(a) an aziridine-modified polyurethane of the structure wherein:

A is the residue of a polyether polyol or polyester polyol having avalence of n,

R is a hydrocarbon radical containing at least two carbon atoms,

R is hydrogen, halogen, lower alkoxy, or a radical of the structure CHR"R" is hydrogen or a lower alkyl radical, n is an integer from 2 to 10,and x is an integer from 1 to 2, and

17 18 (b) a sulphur-containing reductive disulphide-splitting FOREIGNPATENTS agent. 2. The dispersion of claim 1 wherein the said agent919861 2/1963 Great Bntam 260 AM is an alkali metal bisulphite. DONALDE. CZAJA, Primary Examiner References Cited 5 H. S. COCKERAM, AssistantExaminer UNITED STATES PATENTS U.S. Cl. X.R. 3,523,750 8/1970 Tesoro.8277.6; 26075 TN, 77.5 R, 77.5 AM, 29.2

